As a lighting device of the related art, there is a lighting device that forms a line beam which has a thin irradiation width and a long irradiation surface in a near and far direction. There is a lighting device that uses a semiconductor laser as a light source and has a rod lens which forms irradiation light in a line shape. FIG. 28 shows a lighting device described in PTL 1.
In FIG. 28, emission light from laser beam source 1 is rendered to substantially parallel light by a collimator lens 4 including lens 2 and lens 3, and becomes a small circular light ray. Light spreads in only one direction by rod lens 5 of which a curvature of an emission side is constant in the one direction, and thin line beam 7 is formed on irradiation surface 6.